ash: remove limitation on fd# length

"echo text >&0000000000002" works as you would expect,
"echo text >&9999999999" properly fails instead of creating a file
named "9999999999".

function                                             old     new   delta
expredir                                             219     232     +13
readtoken1                                          3045    3053      +8
parsefname                                           204     201      -3
isdigit_str9                                          45       -     -45
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 2/1 up/down: 21/-48)            Total: -27 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 13 insertions, 7 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 39455c7c5..9da3e956a 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -557,10 +557,9 @@ static void trace_vprintf(const char *fmt, va_list va);
 #define is_in_name(c)   ((c) == '_' || isalnum((unsigned char)(c)))
 
 static int
-isdigit_str9(const char *str)
+isdigit_str(const char *str)
 {
-        int maxlen = 9 + 1; /* max 9 digits: 999999999 */
-        while (--maxlen && isdigit(*str))
+        while (isdigit(*str))
                 str++;
         return (*str == '\0');
 }
@@ -9661,7 +9660,7 @@ expredir(union node *n)
                                 if (fn.list == NULL)
                                         ash_msg_and_raise_error("redir error");
 #if BASH_REDIR_OUTPUT
-                                if (!isdigit_str9(fn.list->text)) {
+                                if (!isdigit_str(fn.list->text)) {
                                         /* >&file, not >&fd */
                                         if (redir->nfile.fd != 1) /* 123>&file - BAD */
                                                 ash_msg_and_raise_error("redir error");
@@ -12011,12 +12010,19 @@ fixredir(union node *n, const char *text, int err)
         if (!err)
                 n->ndup.vname = NULL;
 
+        if (LONE_DASH(text)) {
+                n->ndup.dupfd = -1;
+                return;
+        }
+
         fd = bb_strtou(text, NULL, 10);
         if (!errno && fd >= 0)
                 n->ndup.dupfd = fd;
-        else if (LONE_DASH(text))
-                n->ndup.dupfd = -1;
         else {
+                /* This also fails on very large numbers
+                 * which overflow "int" - bb_strtou() does not
+                 * silently truncate results to word width.
+                 */
                 if (err)
                         raise_error_syntax("bad fd number");
                 n->ndup.vname = makename();
@@ -12702,7 +12708,7 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
                 if ((c == '>' || c == '<' IF_BASH_REDIR_OUTPUT( || c == 0x100 + '>'))
                  && quotef == 0
                 ) {
-                        if (isdigit_str9(out)) {
+                        if (isdigit_str(out)) {
                                 PARSEREDIR(); /* passed as params: out, c */
                                 lasttoken = TREDIR;
                                 return lasttoken;